Fistula-in-Ano: for Rural Patients

By Dr. J. Gnanaraj
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Published: Sep 2016

What is a Fistula-in-Ano?

A Fistula-in-Ano is an abnormal connection between the peri-anal skin and the anal canal. It is a hollow tortuous tract lined by granulation tissue and epithelial cells that are similar to the covering of the skin and anal canal. It does not completely heal unless it is correctly treated and frequently causes pain and abscess formation.

It starts as a small abscess that bursts through the inner and outer opening and with incomplete healing the tract forms. Sometimes there may be one inner opening and two or more outer openings. Although the symptoms are mild it could significant affect the quality of life.

How common is the condition?

The Fistula-in-Ano has been around for thousands of years. In fact, it was Hippocrates in 430 BC who described the use of Seton for curing the Fistula. St. Mark’s hospital in London is devoted entirely to the treatment of the Fistula.

The anal abscess occurs in 26-38% adults in developing countries and the incidence of Fistula is about 8-12% per 100,000 populations. The incidence is about half in women.

What should the patients know about the anatomy?

There are two valves or sphincters that control the lower portion of the intestine. One is the external sphincter which is a voluntary sphincter or has muscles that could be voluntarily manipulated. It has three portions namely the subcutaneous, superficial and deep portions. Just inside it is the internal sphincter which is an involuntary one or has smooth muscles that is under automatic nerve control. Puborectalis and levator ani muscles are those that are very important in continence of stools and are located above the two muscles.

The external opening is easy to see while the internal opening might be difficult to visualize. The fistulae start as infection of the anal glands that are found in between the external and internal sphincters. These glands drain into the anal canal and if the opening is blocked, an abscess forms that can burst through the skin. This and the gravity explain what is called the Goodsalls rule about the internal opening. If the external opening is in the anterior half [front half] then the tract is straight and the internal opening is directly in line with the external opening. If the external opening is at the back half then it has a curved tract and the internal opening is always at the center on the posterior side. The internal opening is generally at the dentate line above the sphincter.

Are there any other causes for Fistula-in-Ano?

The most common cause as mentioned earlier is the infection of the anal gland. However they can be secondary to trauma (e.g., rectal foreign bodies), Crohn disease, anal fissures, carcinoma, radiation therapy, actinomycoses, tuberculosis, and lymphogranuloma venereum secondary to chlamydial infection. In India tuberculosis is more common than the other causes while Crohn disease is a more common secondary cause in the West.

Are there any other things that we should know about the types of Fistula?

The most common type [70%] is the inter-sphincteric one described earlier where the tract is in between the two sphincters. The next most common is the trans-sphincteric one where the tract goes through the muscles of the sphincters [25%]. The supra–sphincteric one is also called a High Fistula as it often has a blind tract going up above the sphincter. This occurs in about 4% while the rare extrasphincteric one follows trauma or secondary to causes like tuberculosis, Crohns, etc.

Do we need any special tests?

Generally no specific tests other than clinical examination are necessary for most of the fistulae. However for complex ones tests like the following could be carried out:

Fistulography: X-rays following injection of contrast material are useful only in about half the patients as it might not be very accurate

Special endo-anal ultrasonography is a new technique and has similar limitation of being only 50% accurate

CT scan and MRI could be more accurate [80%] but are expensive

The most accurate method is an examination under anesthesia and injecting hydrogen peroxide or dye during the procedure

What are the available treatment options?

FISTULOTOMY: The most common operation carried out is called Fistulotomy. Here a probe is passed from the external to internal opening and all the tissues from the skin are divided right up to the tract. It is important to make sure that the healing takes place from the deep end. The superficial or skin end has much better blood supply and heals easily while the tract has poor blood supply and heals very slowly. If natural healing is allowed, then there is recurrence of Fistula.

SETONS: This could be used alone or with Fistulotomy or in staged manner. These are considered for complex or recurrent fistulae. Single stage Seton treatment involves tightening the seton so that it cuts through progressively over a period of two to three months. It could be combined with Fistulotomy after a High Fistula becomes a low one. In the two staged procedure the seton is used for drainage of the deep portion after cutting the skin or superficial tissue and lets the Fistula heal slowly over few months.

MUCOSAL FLAPS: These may be tried for High Fistula and involved covering the internal opening with the rectal inner lining. However the results are not very encouraging as far as recurrence rates are concerned.

LIFT PROCEDURE: This is a recently described procedure where the Fistula tract is dissected from external to internal area and the internal opening is closed with a suture and the wound is left open to heal. In the Bio-Lift procedure biological material is used to reinforce the closure of the internal opening. However the drawback is that only few surgeries have been carried out and sufficient long term follow up is not available.

FISTULA CLIP CLOSURE: One of the latest techniques is the use of super-elastic clip made of OTSC to close the internal opening after dissection of the tract. The elastic nature allows infrequent break down.

EXPANDED ADIPOSE DERIVED STEM CELLS: This is another experimental high tech technique where no dissection is necessary and produces natural healing.

THE INDIAN TECHNIQUES: This minimally invasive procedure involved cauterization of the internal opening and regular curettage and draining of the tract through the external opening.

TRACT CAUTERIZATION: This is another rural technique practiced in India where sclerosants are injected to the tract after cauterization with electric wire. This would destroy the epithelial cells of the tract and induce healing by fibrosis.

DIVERSION: Finally in complex patients diversion of feces through colostomy has been carried out to facilitate healing and the colostomy is closed after healing.

Why are there so many options?

Unfortunately, despite being around for over 2000 years there is no simple treatment that cures the complex Fistula. Hence in rural areas the minimally invasive procedures followed by the traditional Fistulotomy and setons are probably the best options. However the success depends on the post-operative management.

What are the facilities available at SEESHA?

The facilities minimally invasive procedures like electro-cauterization procedures and injection therapy and the internal opening ligation technique and the Fistulotomy and the seton techniques are available at the SEESHA Karunya community hospital at Karunya at the SEESHA surgical camps at Bethesda Hospital Aizawl, Sielmat Christian Hospital at Churachandpur at Manipur, Family Health Hospital at Dimapur and the other places.

Dr. J. Gnanaraj MS, MCh [Urology], FICS, FARSI, FIAGES is a urologist and laparoscopic surgeon trained at CMC Vellore currently working as Director of Medical Services of the charitable organization SEESHA and Adjunct Professor in Karunya University. He has special interest in rural surgery and during the last three decades of service in rural areas helped 23 rural hospitals start minimally invasive surgeries. Karunya is now recognized as center for excellence in innovation for rural surgery by Lancet Commission on Global Surgery. He has over 200 publications. He received the Barker Memorial award from the Tropical Doctor for the work regarding surgical camps in rural areas. He is also the recipient of the Innovations award of Emmanuel Hospital Association for health insurance programs in remote areas and the Antia Finseth innovation award for Single incision Gas less laparoscopic surgeries. Recently, he was awarded the Lockheed Martin innovations award by the Department of Science and Technology of Indian Government and the Lockheed Martin Group (USA)